def print_gobang_board(size):
    if size < 5:
        print("棋盘大小至少为5x5,请重新输入。")
        return

    # 打印上边界
    print("┌" + "┬" * (size - 1) + "┐")

    # 打印中间行和分隔线
    for i in range(size-1):
        print("├" + "┼" * (size - 1) + "┤")

    # 打印下边界
    print("└" + "┴" * (size - 1) + "┘")


# 获取用户输入的棋盘大小
size = int(input("请输入棋盘大小："))

# 打印棋盘
print_gobang_board(size)
